| Cup Winners Cup 1980/1981 - Appearances as Referee |  |
 |
 |
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| 01/10/1980 | West Ham United | - | Castilla CF | 5:1 aet | - | - | - |
| 17/03/1981 | SL Benfica | - | Fortuna Düsseldorf | 1:0 | - | - | - |
| Cup Winners Cup 1980/1981 - Appearances as Referee | |
|
|
||||
| 01/10/1980 | West Ham United | - | Castilla CF | 5:1 aet | - | - | - |
| 17/03/1981 | SL Benfica | - | Fortuna Düsseldorf | 1:0 | - | - | - |
| Complete name: | Johannes Nicolaus Ignacius Keizer |
| Born: | 06/10/1940 |
| Place of birth: |
Volendam, 
Netherlands |
| Nationality: |
Netherlands |